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TOPIC: Source and Sink - Injection velocity

Source and Sink - Injection velocity 13 years 1 month ago #2672

  • mat.deiber
  • mat.deiber's Avatar
Hello,

I have some issues with the implementation of a velocity in a source and in a sink with TELEMAC-3D V5P9.

I am using the following command to implemente a source and a sink in my model with a discharge of -40m3/s for the sink and +40 m3/s for the source with constant injection velocities at the sink and source:

/
/ SOURCES
/

ABSCISSAE OF SOURCES =454528.565;455561.693
ORDINATES OF SOURCES =2757554.400 ;2756963.085
ELEVATIONS OF SOURCES =-6;-3
WATER DISCHARGE OF SOURCES =-40;+40
VALUE OF THE TRACERS AT THE SOURCES=31;45;38;50
VELOCITIES OF THE SOURCES ALONG X=1.64;-1.64
VELOCITIES OF THE SOURCES ALONG Y=0.95;0.95

When the model run without the command 'VELOCITIES OF THE SOURCES ALONG X and Y' I got the result i expect (figure 1 ).C:\fakepath\SinkSource-novelocity.jpg

However when the command 'VELOCITIES OF THE SOURCES ALONG X and Y' is activate in the model, something I can't explain (strong current and opposite direction) appear at the sink.

C:\fakepath\SinkSource-velocity.jpg

So how should I implement the velocity properly at the sink (a kind of suction velocity)?

Ideally I'd like the default injection velocity at the sink (no momentum) and an injection velocity at the source of 1.8m/s (if I put 0 as an injection velocity for the sink, I got the same funny results), could someone advise me, the best way to proceed?

Thanks in advance for your help and regards,

Mathieu
C:\fakepath\SinkSource-novelocity.jpg
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Re: Source and Sink - Injection velocity 12 years 9 months ago #3619

  • a.weisgerber
  • a.weisgerber's Avatar
Mathieu

Your message unfortunately slipped through our net. If help is still needed, please could you re-post the pictures as it is difficult to understand your post otherwise?

Thank you
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Re: Source and Sink - Injection velocity 12 years 9 months ago #3625

  • jmhervouet
  • jmhervouet's Avatar
Hello,

You can see how the momentum is injected at sources in subroutine trisou.f (at the end of the subroutine). When the discharge is negative it raises theoretical problems on the momentum we should inject, should we inject a negative momentum ? I am not sure. You can cancel the momentum injection by putting in the formula something like MAX(Q,0.D0) instead of Q. If it works we can think of putting this in library for everyone.

With best regards,

Jean-Michel Hervouet (currently in Saigon for a Telemac training session)
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